Revert of Reduce ActiveDOMObjects from core/

third_party/WebKit/Source/core/fileapi/FileReader.h

Index: third_party/WebKit/Source/core/fileapi/FileReader.h
diff --git a/third_party/WebKit/Source/core/fileapi/FileReader.h b/third_party/WebKit/Source/core/fileapi/FileReader.h
index 0f6b262af05fd77fccb9617bea1dfa086f8c8825..0fef1786c4f010c03e50e31241de0d22ce257808 100644
--- a/third_party/WebKit/Source/core/fileapi/FileReader.h
+++ b/third_party/WebKit/Source/core/fileapi/FileReader.h
@@ -32,7 +32,7 @@
 #define FileReader_h
 
 #include "core/CoreExport.h"
-#include "core/dom/ContextLifecycleObserver.h"
+#include "core/dom/ActiveDOMObject.h"
 #include "core/events/EventTarget.h"
 #include "core/fileapi/FileError.h"
 #include "core/fileapi/FileReaderLoader.h"
@@ -49,7 +49,7 @@
 class ExecutionContext;
 class StringOrArrayBuffer;
 
-class CORE_EXPORT FileReader final : public RefCountedGarbageCollectedEventTargetWithInlineData<FileReader>, public ContextLifecycleObserver, public FileReaderLoaderClient {
+class CORE_EXPORT FileReader final : public RefCountedGarbageCollectedEventTargetWithInlineData<FileReader>, public ActiveDOMObject, public FileReaderLoaderClient {
     DEFINE_WRAPPERTYPEINFO();
     REFCOUNTED_GARBAGE_COLLECTED_EVENT_TARGET(FileReader);
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(FileReader);
@@ -77,12 +77,13 @@
     FileError* error() { return m_error; }
     void result(StringOrArrayBuffer& resultAttribute) const;
 
-    void contextDestroyed() override;
+    // ActiveDOMObject
+    void stop() override;
     bool hasPendingActivity() const override;
 
     // EventTarget
     const AtomicString& interfaceName() const override;
-    ExecutionContext* executionContext() const override { return ContextLifecycleObserver::executionContext(); }
+    ExecutionContext* executionContext() const override { return ActiveDOMObject::executionContext(); }
 
     // FileReaderLoaderClient
     void didStartLoading() override;